POLR1G
RNA Polymerase I Subunit G
Gene Information Card
| Symbol | POLR1G |
|---|---|
| Full Name | RNA Polymerase I Subunit G |
| Gene Type | protein-coding |
| Chromosomal Location | 13q12.2 |
| NCBI Gene ID | 6642 ncbi.nlm.nih.gov/gene/6642 |
| Ensembl ID | ENSG00000102468 |
| UniProt ID | Q9H9Y6 |
| OMIM ID | 617471 |
| HGNC ID | 30084 |
| Aliases | RPA34, RPA34.5, RPA39, A34.5, PAF53 |
Description
POLR1G encodes a subunit of RNA polymerase I, the enzyme responsible for transcribing ribosomal RNA (rRNA) in the nucleolus. This subunit is essential for the assembly and stability of the Pol I complex and plays a role in the initiation and elongation phases of rRNA transcription. Mutations in POLR1G are associated with Treacher Collins syndrome and may contribute to cancer development.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Treacher Collins syndrome 4 | Loss-of-function mutations impair Pol I activity, reducing rRNA synthesis and affecting craniofacial development | OMIM #618939 |
| Colorectal cancer | Somatic mutations and altered expression may disrupt ribosome biogenesis, promoting tumorigenesis | COSMIC, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 15.2 | Medium |
| Lymph node | 12.8 | Medium |
| Brain | 10.5 | Medium |
| Liver | 8.3 | Low |
| Heart | 7.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 14.5 | Cervical cancer cell line |
| HEK293 | 12.3 | Embryonic kidney |
| K562 | 11.0 | Leukemia cell line |
| HepG2 | 9.8 | Liver cancer cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | <0.01% | Loss of start codon, likely loss of function |
| c.325C>T (p.Arg109Trp) | Missense | <0.01% | Impaired Pol I complex assembly |
| c.487G>A (p.Gly163Arg) | Missense | <0.01% | Reduced rRNA transcription |
Mutation functional classification
Loss of Function (LOF)
Most pathogenic mutations are loss-of-function, reducing Pol I activity and rRNA synthesis.
Gain of Function (GOF)
No evidence of gain-of-function mutations.
Dominant Negative (DN)
Some missense mutations may exert dominant-negative effects by disrupting Pol I complex assembly.
View complete mutation data：
Gene Ontology (GO)
| • DNA-directed 5'-3' RNA polymerase activity | • nucleolus |
| • ribosome biogenesis | • transcription initiation from RNA polymerase I promoter |
| • RNA polymerase I complex |
Pathways
• RNA polymerase I transcription
• rRNA processing
• Ribosome biogenesis in eukaryotes
Protein Summary
POLR1G encodes a 34.5 kDa protein (RPA34) that is a stoichiometric subunit of RNA polymerase I. It contains a conserved RNA polymerase domain and interacts with other Pol I subunits to form the active enzyme complex. The protein localizes to the nucleolus and is required for efficient rRNA transcription.
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